At least two Government ministers have already been questioned by police investigating the cash-for- honours allegations, it emerged today.

A spokeswoman for Science Minister Lord Sainsbury confirmed he had been questioned by detectives during their investigation into whether or not people have been given honours in return for making financial donations to political parties.

She would not reveal when or where the Parliamentary Under Secretary of State for Science and Innovation had been interviewed but added that he had not been placed under caution.

Meanwhile, sources revealed that Lord Sainsbury was "not the first or the only" minister to be quizzed.

One report, in a national newspaper, said Trade Minister and former party chairman Ian McCartney had also been questioned.

In April, Lord Sainsbury faced a possible probe into an alleged breach of the ministerial code after admitting he had failed to disclose a £2m loan he had made to the Labour Party - despite publicly stating that he had.

He apologised for "unintent- ionally" misleading the public, blaming a mix-up between that loan and a donation - also of £2m - he had made at about the same time.

Scotland Yard was accused yesterday of whipping up a "media circus" over the investigation. Criticism of the force came from Labour's chief fundraiser Lord Levy, who was arrested on Wednesday.

He denounced his arrest as "unnecessary, disproportionate and theatrical" and insisted once more that he was innocent.

Lord Levy and Lord Sainsbury are two names confirmed among 48 people questioned so far by the Metropolitan Police's Specialist Crimes Directorate.